In a fifth-generation wireless access system standard new radio (NR), a basic unit in frequency domain is a subcarrier, and a basic unit in time domain is an orthogonal frequency division multiplexing (OFDM) symbol. A resource element (RE) is a minimum physical resource, and includes one subcarrier in one OFDM symbol.
In the NR, a basic scheduling unit in time domain is a timeslot (timeslot) or mini-slot, and the slot or mini-slot includes several OFDM symbols. As shown in FIG. 1, the slot may be divided into a control area and a data area, and a downlink control channel (PDCCH) carries downlink control information (DCI) and is transmitted in the control area. A resource element group (REG) is a time-frequency resource unit that constitutes a time-frequency resource for the downlink control channel in the control area.
In an existing solution, the downlink control channel is transmitted by using a REG of a fixed structure, and configuration is inflexible.